An Auckland home that was the scene of more than a decade of sexual offending against vulnerable, runaway girls could be seized by the Crown.

Derek Lester King, 66, listened to lawyers argue over the future of his home at a forfeiture hearing at the High Court in Auckland yesterday.

King, who previously had name suppression, was found guilty in August of 16 sex and drug charges that stemmed back to the late 1990s.

The retired architect, who appeared in court with his white hair tied in a low pony tail and sporting a green jacket, lured teenage runaways to his home on the fringe of Parnell to exchange drugs, alcohol and bus fares for sex.

The prosecution argued that King's home, which has a government valuation of $520,000, should be confiscated by the court to deter future offending.

Prosecution lawyer June Jelas said a psychiatric report showed there was a ''high risk'' of reoffending if King was released to his home.

King established his sexual habits at the house over three decades and specifically designed it to lure vulnerable girls in for sex, she said.

''He made alterations to the property to make it more attractive.'' Mattresses were kept downstairs for street children and a key was left out.

''He allowed [victims] to personalise the home by placing their tag in it.''

There were also concerns young people would continue staying at his home while he served his prison sentence, she said.

Justice Kit Toogood said he would consider preventative detention when sentencing King next month and it was likely he would be aged in his late seventies before being considered for release.

To succeed with the forfeiture bid, the prosecution must convince the judge the house actually posed a risk of triggering King's offending, rather than merely being a venue for sex.

The decision could potentially set a precedent for future sexual offence cases. A house has never been confiscated from a convicted sexual offender sentenced to preventative detention.

Justice Toogood reserved his decision on forfeiting the home until sentencing on December 12.

Defence lawyer Nicholas Wintour asked for a formal valuation of the house before a final decision was made.

During the trial the jury heard how King would invite young girls living on the streets into his home.

Witnesses described how he wandered his home wearing just a bathrobe and making requests for victims to bring young, skinny girls to his house.

His defence argued that although he paid for sex, he believed the girls were of legal age.